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Vitamin D: signs and symptoms of deficiency in the sunshine hormone

At a glance

  1. Vitamin D deficiency is a silent saboteur of good health.
  2. We usually don’t notice when we’re deficient in vitamin D.
  3. Low vitamin D is common even for those without an identifiable risk, for example over 50% of white Europeans had levels below 50 nmol/L in winter/spring.
  4. Signs of low vitamin D that you might not know about include: low energy, low mood, thinning hair, and chronic aches and pains in bones, muscles and joints.

What is vitamin D?

A person putting their hands in a heart shape in front of the vitamin producing sun.

Vitamin D isn’t your typical vitamin – it’s quite unique compared to most others. Technically speaking, vitamin D is actually a pro-hormone, as your body converts it into an active hormone.

Two main dietary forms of vitamin D are vitamin D2 (ergocalciferol) which you get from plant sources, and D3 (cholecalciferol) from animal sources. Your body can also produce vitamin D3 when your skin is exposed to the sun, which is the best source. That’s why it’s often called the “sunshine vitamin” or “sunshine hormone”. However, we often can’t get enough of these sources so vitamin D can also be obtained from supplements.

This article will talk about what vitamin D deficiency is, the signs and symptoms of low vitamin D levels that you should watch out for, how to get your levels checked, and how you can be part of cutting-edge research hoping to uncover more factors associated with vitamin D levels.

What is vitamin D deficiency?

Vitamin D deficiency happens when you don’t get enough vitamin D from sources like sunlight or diet.

Low vitamin D is very common

Low vitamin D is common even for those without an identifiable risk factor – particularly by the end of winter when the body’s vitamin D reserves, built up during the summer months have been exhausted. For example, over 50% of white Europeans had levels below 50nmol/L in winter/spring. Even in the summer months, many people are unknowingly deficient.

Vitamin D deficiency has also been linked with a host of medical conditions. We discuss these and the benefits of vitamin D, including how much you need and, importantly, how to get it, in our other article ‘Vitamin D: a gateway to good health’.

Signs and symptoms linked with low vitamin D

Vitamin D deficiency isn’t always easy to notice, as most people with suboptimal or deficient levels experience no symptoms at all. Severe deficiency can cause rickets in children and osteomalacia in adults.

Signs of rickets in children:

  • Skeletal deformities – children with rickets may have thickening of the ankles, wrists and knees, in severe cases bowlegs, soft skull bones and, rarely, bending of the spine
  • Weakened and painful bones – in severe cases, bones may be more prone to fractures, and children may not want to walk and may waddle
  • Tiredness – children with rickets may tire easily
  • Poor growth – children with rickets may grow up to be shorter than average
  • Poor dental health – including weakened tooth enamel, cavities and delayed tooth eruption

Children with severe vitamin D deficiency may show bowing of the legs (where the knees curve outwards even when the ankles are together). It’s common in children up until the age of 3 or 4, but if it continues after this age, this should be checked by a doctor.

In adults, there may be tenderness of the breastbone or tibia (shin bone), amongst other symptoms that are worth keeping an eye out for, which can be found in our image below.

Warning in a circle with a green border

It’s important to note that these symptoms below certainly aren’t exclusive to vitamin D and may be caused by something else. It’s therefore always best to consult your GP if you’re concerned and get your vitamin D levels checked to rule out deficiency as a cause.

Here are some signs and symptoms that may be linked to vitamin D deficiency; evidence isn’t definite but can be found at the end of this article:

An infographic spider diagram with a blue background with the title: 'symptoms that might be linked to low vitamin D in adults.' at the top Symptoms listed are: low mood, poor sleep, fatigue, weight gain, poor gut health, hair loss, low back pain, bone and muscle pain, frequent infections, poor skin (psoriasis and eczema), poor wound healing. An icon of binoculars is in the centre.

How to get your vitamin D levels checked

A person testing their vitamin D levels with a finger prick blood test at home.

The only way to know for sure if you have a vitamin D deficiency is to take a blood test. It’s often catchily named the ‘25-hydroxy vitamin D blood test’. The results of the test can also help to establish the best supplementation dose for your personal needs.

Did you know lightbulb icon in a circle with a green border

Your GP may arrange this or there are a number of private suppliers that offer home vitamin D tests for around £39 (for example, Medichecks, Thriva and Healthily).

What the results from a vitamin D blood test mean

A clipboard with a piece of paper that says 'Are you getting enough vitamin D?' Yes or No.

Different labs report vitamin D blood levels using different units. In the UK, it’s usual to use nmol/L but you might see ng/mL, which aren’t the same. The methods of testing can also vary from lab to lab.

To convert ng/mL to nmol/L, multiply by 2.5 (50 ng/mL = 125nmol/L)

To convert nmol/L to ng/mL, divide by 2.5 (125nmol/L is equivalent to 50ng/mL)

The reference ranges are not clearly defined because expert opinions tend to differ. However, there is general medical consensus that individuals with test results of less than 30 nmol/L are deficient and this should be corrected, whilst levels above 75 nmol/L are considered sufficient.

NHS guidance currently states that if vitamin D levels are less than 25 nmol/L the patient is considered deficient and should be prescribed a high dose vitamin D for up to 7 weeks. Calcium intake should also be assessed and dietary advice or supplements advised as appropriate. Upon completion of initial therapy, vitamin D and calcium should be reassessed and patients should be advised to continue an over-the-counter vitamin D supplement of 800–2000 IU daily long term.

Meanwhile, doctors in the functional and lifestyle medicine community ask, ‘how much do we need to not only support bone health but to help prevent an array of health conditions and diseases?’ They conclude the right amount varies from person-to-person but suggest somewhere between 75 – 150 nmol/L.

Get involved: Your story matters

A phone showing the Vitamin D Check in the Evergreen Life app where you can check for other risk factors of low vitamin D, and learn more about vitamin D. Beside the phone is a piece of paper with the words 'Share your story' on it.

How does your lifestyle compare to others’? Through questionnaires in the Evergreen Life app, our community is sharing information about their wellness habits and vitamin D levels, so we can all learn from each other how to live a healthier, happier life. With your help, we can explore more factors relating to vitamin D, as well as other health and wellbeing topics.

We’re specifically looking for more people who’ve taken a vitamin D blood test to share their experience by completing the in-app questionnaires. We’re particularly interested to hear from women with gynaecological issues such as endometriosis, polycystic ovary syndrome and fibroids, to understand if vitamin D deficiency is important to these, as a few small studies have suggested it could be.

So if you have a vitamin D story, please get in touch as we’d love to hear from you.

With what you’ve shared already in the app community, here’s what we’ve found:

A graph showing the correlations between various health and lifestyle factors and having a vitamin D deficiency.

For a full explanation of how these figures are generated, please see the bottom of this page.

If you’d like to join the app community to contribute to and learn from this exciting research, you can download the Evergreen Life app and take the in-app questionnaires, including the Vitamin D Check. If you choose to do a vitamin D test, you can also record your results in your Evergreen Life app here:

A GIF to show how to record your vitamin D level result in the personal health record (PHR) section of the Evergreen Life app.

Reviewed by:

Anna Keeble MA BA Wellbeing Expert

Dr Claire Marie Thomas MRCGP DFSRH DTMH DipNLP MBChB BMedSci Medical Expert

Statistical disclaimers for correlates graph:

Using information from over 20,000 Evergreen Life users, these figures are derived from multivariate Linear Probability Models (LPMs) (https://bit.ly/3aKaCeG), where we control for users’ gender, age and index of multiple deprivation (IMD). A “more deprived area” is defined as those users who live in the most deprived 30% of England and Wales, using the Index of Multiple Deprivation (https://www.gov.uk/government/statistics/english-indices-of-deprivation-2019), for the users’ Lower-layer Super Output Area (LSOA) associated with their postcode (https://www.ons.gov.uk/methodology/geography/ukgeographies/censusgeography). Obese is defined as a BMI > 30 and Overweight is defined as 25< BMI <30 (https://www.nhs.uk/conditions/obesity/)

References by signs:

Bone pain

Habib AM, Nagi K, Thillaiappan NB, et al. (2020) Vitamin D and Its Potential Interplay With Pain Signaling Pathways. Front Immunol.11: 820 (doi: 10.3389/fimmu.2020.00820).

NHS (2021) Symptoms Rickets and osteomalacia. NHS.

Scientific Advisory Committee on Nutrition (SCAN) (2016) Vitamin D and Health. Scientific Advisory Committee on Nutrition (SCAN).

Muscle pain     

NHS (2021) Symptoms Rickets and osteomalacia. NHS.

Ruffin JM. (1941) THE DIAGNOSIS AND TREATMENT OF MILD VITAMIN DEFICIENCIES: A CLINICAL DISCUSSION. JAMA.117: 1493–1496 (doi:10.1001/jama.1941.02820440001001).

Tague SE, Clarke GL, Winter MK, et al. (2011) Vitamin D deficiency promotes skeletal muscle hypersensitivity and sensory hyperinnervation. J Neurosci. 31: 13728-38 (doi: 10.1523/JNEUROSCI.3637-11.2011).

Muscle weakness

Halfon M, Phan O and Teta D (2015) Vitamin D: A Review on Its Effects on Muscle Strength, the Risk of Fall, and Frailty. BioMed Research International Article ID 953241 (doi: (10.1155/2015/953241).

Nair R and Maseeh A (2012) Vitamin D: The “sunshine” vitamin. J Pharmacol Pharmacother. 3: 118-26. (doi: 10.4103/0976-500X.95506).

NHS (2021) Symptoms Rickets and osteomalacia. NHS.

Scientific Advisory Committee on Nutrition (SCAN) (2016) Vitamin D and Health. Scientific Advisory Committee on Nutrition (SCAN).

Gut health

Fakhoury HMA, Kvietys PR, Alkattan W, et al. (2020) Vitamin D and intestinal homeostasis: Barrier, microbiota, and immune modulation. The Journal of Steroid Biochemistry and Molecular Biology 200: 105663 (doi: doi.org/10.1016/j.jsbmb.2020.105663).


Diabetes.co.uk (2022) Tiredness and Diabetes Diabetes.co.uk

NHS (2021) Symptoms Rickets and osteomalacia. NHS.

Nowak A, Boesch L, Andres E, et al. (2016) Effect of vitamin D3 on self-perceived fatigue A double-blind randomized placebo-controlled trial. Medicine 95: e5353 (doi: 10.1097/MD.0000000000005353).

Pennisi M, Malaguarnera G, Di Bartolo G, et al. (2019) Decrease in Serum Vitamin D Level of Older Patients with Fatigue. Nutrients 11:2531 (doi: 10.3390/nu11102531).

Roy S, Sherman A, Monari-Sparks MJ, et al. (2014) Correction of Low Vitamin D Improves Fatigue: Effect of Correction of Low Vitamin D in Fatigue Study (EViDiF Study). N Am J Med Sci. 6: 396-402. (doi: 10.4103/1947-2714.139291).

Scientific Advisory Committee on Nutrition (SCAN) (2016) Vitamin D and Health. Scientific Advisory Committee on Nutrition (SCAN). Page 190.

Respiratory tract infection

Urashima M, Segawa T, Okazaki M, et al. (2010) Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. he American Journal of Clinical Nutrition 91: 1255–1260 (doi: 10.3945/ajcn.2009.29094).

Low mood depression

Anglin RES, Samaan Z, Walter SD, et al. (2013) Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry. 202: 100-7 (doi: 10.1192/bjp.bp.111.106666.)

Bani-issa W, Eldeirawi K, Harfil S, et al. (2017) Vitamin D Deficiency and Its Determinants in Adults: A Sample from Community-Based Settings in the United Arab Emirates. International Journal of Endocrinology Article ID 3906306 (doi: 10.1155/2017/3906306).

Holmøy T and Moen SM (2010) Assessing vitamin D in the central nervous system. Acta Neurologica Scandanavica 122: 88–92 (doi: 10.1111/j.1600-0404.2010.01383.x).

Shaffer JA, Edmondson D, Wasson LT, et al. (2014) Vitamin D supplementation for depressive symptoms: a systematic review and meta-analysis of randomized controlled trials. Psychosom Med. 76: 190-6 (doi: 10.1097/PSY.0000000000000044).

Tooth decay

NHS (2021) Symptoms Rickets and osteomalacia. NHS.

Scientific Advisory Committee on Nutrition (SCAN) (2016) Vitamin D and Health. Scientific Advisory Committee on Nutrition (SCAN). Page 190.

Uterine fibroids

Baird DD, Hill MC, Schectman JM, et al. (2013) Vitamin D and the risk of uterine fibroids. Epidemiology. 24: 447-53. (doi: 10.1097/EDE.0b013e31828acca0).

Ciavattini A, Carpini GD, Serri M, et al. (2016) Hypovitaminosis D and “small burden” uterine fibroids: Opportunity for a vitamin D supplementation. Medicine (Baltimore) 95: e5698 (doi:10.1097/MD.0000000000005698).        

Ciebiera M, Włodarczyk M, Ciebiera M, et al. (2018) Vitamin D and Uterine Fibroids-Review of the Literature and Novel Concepts. Int J Mol Sci.19: 2051. (doi: 10.3390/ijms19072051).

Kaplan ZAO, Taşçi Y, Topçu HO, et al. (2018) 25-Hydroxy vitamin D levels in premenopausal Turkish women with uterine leiomyoma. Gynecol Endocrinol. 34: 261-264 (doi: 10.1080/09513590.2017.1391774).

Tanha FD, Feizabad E, Farahani MV, et al. (2021) The Effect of Vitamin D Deficiency on Overgrowth of Uterine Fibroids: A Blinded Randomized Clinical Trial. International journal of fertility & sterility 15: 95–100 (doi: 10.22074/IJFS.2020.134567).


Giampaolino P, Corte LD, Foreste V, et al. (2019) Is there a Relationship Between Vitamin D and Endometriosis? An Overview of the Literature. Curr Pharm Des. 25: 2421-2427. (doi: 10.2174/1381612825666190722095401).

Qiu Y, Yuan S and Wang H (2020) Vitamin D status in endometriosis: a systematic review and meta-analysis. Arch Gynecol Obstet. 302: 141-152 (doi: 10.1007/s00404-020-05576-5).

Frequent infections

Aranow C. (2011) Vitamin D and the immune system. J Investig Med. 59: 881-6. (doi: 10.2310/JIM.0b013e31821b8755).

Pearce SHS and Cheetham TD (2010) Diagnosis and management of vitamin D deficiency. BMJ 340: b5664 (doi: 10.1136/bmj.b5664).

Hair loss

Cerman AA, Solak SS and Altunay IK (2014) Vitamin D deficiency in alopecia areata. British Journal of Dermatology 170: 1299-1304 (doi: 10.1111/bjd.12980).

Lin X, Meng X and Song Z (2019) Vitamin D and alopecia areata: possible roles in pathogenesis and potential implications for therapy. American journal of translational research 11: 5285–5300.

Luderer HF and Demay MB (2010) The vitamin D receptor, the skin and stem cells. J Steroid Biochem Mol Biol. 121: 314-6 (doi: 10.1016/j.jsbmb.2010.01.015).

Sanke S, Samudrala S, Yadav A, et al. (2020) Study of serum vitamin D levels in men with premature androgenetic alopecia. Int J Dermatol. 59:1113-1116 (doi: 10.1111/ijd.14982).

Low back pain

Gokcek E and Kaydu A (2018). Assessment of Relationship between Vitamin D Deficiency and Pain Severity in Patients with Low Back Pain: A Retrospective, Observational Study. Anesthesia, essays and researches 12: 680–684. (doi: 10.4103/aer.AER_96_18).

Poor wound healing                 

Razzaghi R, Pourbagheri H, Momen-Heravi M, et al. (2017) The effects of vitamin D supplementation on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial. J Diabetes Complications. 31: 766-772 (doi: 10.1016/j.jdiacomp.2016.06.017).

Poor sleep           

Bahrami A, Rezaeitalab F, Farahmand SK, et al (2021). High-dose Vitamin D Supplementation and Improvement in Cognitive Abilities, Insomnia, and Daytime Sleepiness in Adolescent Girls. Basic Clin Neurosci.12: 339-348. (doi: 10.32598/bcn.2021.1910.1.).

Poor skin                                 

Bikle DD (2011) Vitamin D metabolism and function in the skin. Mol Cell Endocrinol. 347: 80-9 (doi: 10.1016/j.mce.2011.05.017).

European Food Safety Authority (2006) TOLERABLE UPPER INTAKE LEVELS FOR VITAMINS AND MINERALS European Food Safety Authority.

Grant WB. 92016) The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D. Dermatoendocrinol. 8: e1137400 (doi: 10.1080/19381980.2015.1137400).

Mostafa WZ and Hegazy RA (2015) Vitamin D and the skin: Focus on a complex relationship: A review. Journal of advanced research 6: 793–804. (doi: 10.1016/j.jare.2014.01.011).


Lerchbaum E and Rabe T (2014) Vitamin D and female fertility. Curr Opin Obstet Gynecol. 26: 145-50 (doi: 10.1097/GCO.0000000000000065).

Paffoni A, Ferrari S, Viganò P, et al. (2014) Vitamin D Deficiency and Infertility: Insights From in vitro Fertilization Cycles, The Journal of Clinical Endocrinology & Metabolism 99: E2372–E2376 (doi: 10.1210/jc.2014-1802).

Other references:

  1. Bilezikian JP, Formenti AM, Adler RA, et al. (2021) Vitamin D: Dosing, levels, form, and route of administration: Does one approach fit all? Rev Endocr Metab Disord. 22: 1201-1218. (doi: 10.1007/s11154-021-09693-7).
  2. BMJ (2017) Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ 356: i6583 (doi: 10.1136/bmj.i6583).
  3. Dror AA, Morozov N, Daoud A, et al. (2022) Pre-infection 25-hydroxyvitamin D3 levels and association with severity of COVID-19 illness. PLoS ONE 17: e0263069. (doi: 10.1371/journal.pone.0263069).
  4. El-Bahya AAZ, Rasha AR, Gadc MZ, et al. (2018) A Closer Insight into The Role of Vitamin D in Polycystic Ovary Syndrome (Pcos). Glob J Pharmaceu Sci. 6: 555692 (doi: 10.19080/GJPPS.2018.06.555692).
  5. Hahn J, Cook NR, Alexander EK, et al. (2022) Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial BMJ 376: e066452 (doi: 10.1136/bmj-2021-066452).
  6. National Institutes of Health Office of Dietary Supplements (2022) Vitamin D Factsheet for Health Professionals. National Institutes of Health Office of Dietary Supplements.
  7. Rudick BJ, Ingles SA, Chung K (2014) Influence of vitamin D levels on in vitro fertilization outcomes in donor-recipient cycles. Fertil Steril. 101: 447-52 (doi: 10.1016/j.fertnstert.2013.10.008).
  8. Soltani-Zangbar MS, Mahmoodpoor A, Dolati S (2022) Serum levels of vitamin D and immune system function in patients with COVID-19 admitted to intensive care unit. Gene Rep. 26: 101509 (doi: 10.1016/j.genrep.2022.101509).
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Nicky Verity

Nicky Verity is a wellbeing researcher at Evergreen Life. A former clinical pharmacist, Nicky is passionate about empowering others to help themselves.